This application relates to joints, specifically joints that allow for segments connected by such joints to support significant weight as well as to compact efficiently to a stowed configuration, facilitating shipping, storage, and user transport of structures constructed of the same.
Methods of compacting various structures have been known for some time and are very useful for disassembling components of large volume structures to be stowed and transported with much lower volume. Yet, all of these have serious drawbacks that reduce compactability, functionality, and convenience. Telescoping mechanisms, for example, are employed to stow and transport elongated objects such as tripods, projector stands, antennas, seat height adjusters, and the like. These telescoping structures, however, often rely on the friction of the segments to be extended and thus cannot, support significant weight on top without expensive reinforcement locks. Moreover, these structures are inherently hollow and thus generally too weak for supporting weight laterally. Various other compacting or disassembly methods are used in structures like shelter frames, fishing rods, scaffolding, ladders, and the like. In the collapsed configuration, however, these are often stored in somewhat unwieldy, cumbersome arrangements that are frequently still too hefty and awkwardly shaped for convenience. Some other structures, such as pull-out beds, strollers, lawn chairs, and the like include strategically placed joints for folding in usually one dimension, but even in the collapsed state, these structures are still fairly large and relatively difficult to store or transport.
Certain furniture sets, such as those sold by IKEA, while specifically designed to be disassembled, are nonetheless packaged in very large containers that are often difficult to carry and transport. Some structures exist, however, that are constructed almost entirely of substantially similar collapsible components to improve compactability. Examples of such structures are those provided in U.S. Pat. No. 5,024,031 to Hoberman, U.S. Pat. No. 4,437,275 to Ziegler, U.S. Pat. No. 4,276,726 to Derus, and U.S. Pat. No. 3,496,687 to Greenberg et al. While these structures do significantly collapse, the structural components are not directly adjacent to each other in the collapsed state, creating inefficient recesses that waste space and reduce compactability. Other foldable structures collapse in an efficient manner without any wasteful recesses. For example, folding rulers, such as those provided in U.S. Pat. No. 849,638 to Platt, U.S. Pat. No. 1,501,713 to McCaffrey, U.S. Pat. No. 734,013 to Traut and Traut, U.S. Pat. No. 955,314 to Borne, and U.S. Pat. No. 7,111,408 to Critelli and Gilliam, all use joints to significantly compact a plurality of substantially uniform segments whereby the segments are aligned and directly adjacent to one another without wasted space in the stowed configuration. Such an efficiently compacting assembly provided by the foldable rulers would be advantageous in increasing the convenience and compactability of many of the devices listed above. Yet, the collapsible structures discussed above, particularly shelter frames and various furniture pieces, must often support significant weight, for which the joints of the foldable rulers are, unsuitable, as they usually fix the ruler segments in a line with detents or through the friction of shallow complementary depressions, which are specifically designed to easily disengage under force.
Therefore, a joint is desired wherein segments connected by such joints may support significant weight, as well as efficiently compact to a stowed configuration similar to that of foldable rulers.
One way for joints to support significant weight without buckling is to comprise some type of stop mechanism whereby the segments interconnected by the joint do not rotate beyond a certain desired angle. The main related art in this area includes various stop hinges, knuckle joints, and the like, all of which comprise interconnected segments with various stopping mechanisms to inhibit rotation beyond a desired angle. Examples of stop hinges are provided in U.S. Pat. No. 2,803,850 to Hooper, U.S. Pat. No. 6,353,967 to Escobar et al., U.S. Pat. No. 2,852,802 to Seby, U.S. Pat. No. 284,008 to Hass, and U.S. Pat. No. 2,839,779 to Haag. Examples of knuckle joints are provided in U.S. Pat. No. 3,999,246 to Suska, U.S. Pat. No. 3,068,946 to Frisby, U.S. Pat. No. 3,503,130 to Ferguson, U.S. Pat. No. 4,283,811 to George, and U.S. Pat. No. 3,295,699 to Bauernschub. While most such joints would not buckle as easily as those in foldable rulers discussed above, most are still not designed to support significant weight on top except for in especially sturdy and reinforced embodiments. The main problem with the joints mentioned above, however, is that the segments interconnected by these joints generally rotate in the same plane and are thus unable to stackably fold in the same manner as the foldable rulers discussed above when 3 or more segments are interconnected by such joints.